This invention relates to a food product, and to a manufacturing process suitable for commercially producing the said food product. The invention relates particularly to an extruded food product.
Existing extruded fibrous proteins require, post extrusion, the addition of water to open and soften the structure to produce a more organoleptically acceptable food product. This addition of water is absorbed by the extruded material, but can be lost during further processing, cooking or during eating, thus affecting the organoleptic properties of the product. Conversely when the textured protein is cooked in a high moisture sauce, unwanted absorption of water can be experienced, thus making the product soft, over-expanded and organoleptically unacceptable.
An objective of this invention is to stabilise the water content of an extruded piece, at a predetermined moisture level, thus imparting the required eating texture and stabilisation of the product. As a result of this stabilisation of water content, eating qualities, firmness, product colour and flavour can be controlled and thus standardised.
According to one aspect of the invention I provide a method of manufacturing a food product by the addition of soluble proteins in the form of a homogeneous brine to an extruded textured protein piece under vacuum in a mixing vessel, and wherein the said proteins are then coagulated by means of heating, thereby stabilising the product.
By the addition of secondary introduced proteins carried into the product by a brine and then coagulated by means of heat, the water content of the piece is stabilised, thus reducing the tendency for water loss and absorption, thus facilitating a consistent finished product in terms of texture, size and organoleptic properties.
Preferably the protein elements in the said brine are selected from the group consisting of plant proteins, animal proteins, vegetable proteins, cereal protein, tuberous protein, fish protein, fungal protein, and derivatives and mixtures thereof.
The homogeneous brine is preferably based on a solution of water whereby the proteins are solubilised in the said water.
Flavourings and/or oil and/or colorants and/or salts may be contained in the homogeneous brine.
The make up of the brine, moisture level, quantity and type of added proteins such as soya and egg will all affect the resulting texture. Salt and flavour levels will affect solubility of the added proteins and also flavour and colour. These variables can be used to exhibit varying finished product textures and colours as required.
Said addition is made under controlled vacuum conditions in said mixing vessel in order to accelerate the diffusion of the brine into the textured piece, thereby carrying the soluble proteins and other materials into the structure of the textured protein.
The degree of agitation under vacuum can significantly affect the moisture content of the end product and thus impact the finished eating qualities, The degree of heating affects denaturation and coagulation of the proteinaceous brine post hydration.
The heating, which is preferably at atmospheric pressure but could be at some other pressure, is preferably carried out at a humidity above 75%, in order to coagulate the protein, thereby providing stability.
The said heating is preferably carried out at temperatures between 60xc2x0 C. and 90xc2x0 C., specific to the proteins used in the said proteinaceous brine.
Essentially, the process enables an extruded textured piece of fibrous protein to be stabilised with regards to its eating qualities.
By stabilisation, it is possible to manufacture a textured material from non meat protein, which has many of the visual and eating qualities of cooked meat protein.
The extruded textured piece can be in many different forms, size, shape, colour, degree of texturisation and ingredient make up. These differences will be carried through the whole stabilisation process, and will affect the finished product.